# NTSB CHI99LA057: Mooney M20E, N333WS, Tryon, NE, December 31, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 31, 1998, 10:50 local (16:50 UTC) - Place: Tryon, NE - Coordinates: 41.550254, -100.940246 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.5503&lon=-100.9402&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 45572 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI99LA057 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45572/pdf - Page: https://openairdocs.org/ntsb/CHI99LA057 ## Probable cause other maintenance personnel's not correcting a loose cylinder assembly. Factors were loose engine cylinder assembly, fractured cylinder mounting hardware, the roadway, and road sign. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - engine assembly,cylinder - loose (contributing factor) - maintenance,annual inspection - not corrected, other maintenance personnel (cause) - engine installation,mounting bolt - fractured (contributing factor) - Forced landing, descent - emergency - On ground/water collision with object, landing - roll - terrain condition - roadway/highway (contributing factor) - object - sign (contributing factor) ## Analysis While in cruise flight the engine began to lose power. The pilot elected to conduct a forced landing on a roadway due to rough and hilly terrain. The landing was successful; however, during the rollout the right wing impacted a sign, and rotated into a ditch. Subsequent to the accident an examination of the airplane engine revealed #3 cylinder was loose and six cylinder base studs were fractured. The engine had accumulated a total time of 1,100 hours time in service and 31 hours since the last inspection. ## Factual narrative On December 31, 1998, at 1050 central standard time, a Mooney M20E, N333WS, operated by a private pilot, sustained substantial damage during a forced landing following a loss of engine power. The airplane landed on a roadway 35 miles northwest of North Platte, Nebraska, near Tryon, Nebraska. The pilot told authorities that he noted a rise in the exhaust gas temperature just prior to the loss of engine power. The pilot reported no injuries. The personal 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The flight departed North Platte, Nebraska, with an intended destination of Rapid City, South Dakota, at 1035. The pilot sad that after initiating a forced landing he elected to land on a roadway due to rough and hilly terrain. He said that the landing was successful; however, during rollout the right wing contacted a sign, and the airplane rotated into a ditch. An examination of the airplane after the accident revealed that the #3 cylinder was loose from the crankcase and that six studs were broken. The intake pipe for the same cylinder was found broken. The most recent inspection of the airplane and engine occurred on September 25, 1998. The engine had accumulated 31 hours since the inspection and the total time in service of 1,100 hours. ## Aircraft - Registration: [N333WS](https://openairdocs.org/deregistered/N333WS-1999-06-15), registration cancelled 1999-06-15, S/N 323 (OpenAirDocs) - Reported make and model: Mooney M20E - Registry model: [Mooney M20E](https://openairdocs.org/model/mooney-m20e) (registry code 5870212) (OpenAirDocs) - Category: Airplane - Serial number: 323 - Airframe hours: 4632 - Engines: Lycoming IO-360-A1A 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Roger D. Smith - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 25, 1998, 31 hours before - Departed: LBF, NORTH PLATTE, NE - Destination: RAP, RAPID CITY, SD ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 1,435 total, 1,020 in this make and model, 1,387 as pilot in command, 26 in the last 90 days, 12 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 8,000 ft broken - Altimeter: 30.00 inHg - Observed at: LBF, 35 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19981231044249A](https://openairdocs.org/incident/19981231044249A), Dec 31, 1998: Mooney M20E, Tryon, NE, Substantial damage. (.19)On December 31, 1998, at 1050 central standard time, a Mooney M20E, N333WS, operated by a private pilot, sustained substantial damage during a forced… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.